Code Definition

P1550 — Torque Converter Clutch Solenoid Valve

System: Powertrain  |  Type: Manufacturer-Specific  |  Make: Infiniti

About P1550

P1550 is a manufacturer-specific powertrain diagnostic trouble code recorded for Infiniti vehicles. It belongs to the P-prefix family of codes, which covers engine, transmission, emissions, or fuel-system faults.

Scanning & clearing: A generic OBD-II scan tool will usually read and clear powertrain (P) codes. For live data, freeze-frame capture, and bi-directional tests you may need a more capable scan tool that supports the vehicle's ECM protocol.

P1550 is a manufacturer-specific code. The same code string on a different make may have a different meaning. Always confirm the code's definition against the vehicle's service information for the specific make and model under test.

Code Information

The torque converter clutch solenoid valve, also called the lock up solenoid, controls application of the lock up clutch inside the torque converter on these Nissan and Infiniti vehicles. The transmission control function, integrated with the Engine Control Module on many of these vehicles, energises the solenoid to direct hydraulic pressure that mechanically locks the converter, removing slip for better fuel economy and lower transmission temperature at cruise. DTC P1550 is set when the controller detects an improper voltage in the torque converter clutch solenoid valve circuit, indicating an...

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